Generally, organic transition metal complex compounds tend to be influenced by oxygen, water, and compounds having a proton-donor ability. Some kinds of organic transition metal complex compounds decompose by oxidative decomposition, hydrolysis, or elimination decomposition or the like, when being in contact with oxygen, water, or a compound having a proton-donor ability.
In order to synthesize an organic transition metal complex compound with an atom group having a strong electron-donor ability, such as cyclopentadienyl, alkoxy, and carboxyl, a reactant with an atom group having a stronger electron-donor ability is used in many cases, the reactant being made by converting a compound having a proton-donor ability to an alkyl alkali metal salt which has no proton-donor ability. When an organic transition metal complex compound is produced by using this process, however, a desired portion of an organic transition metal complex compound does not react with the alkyl alkali metal salt due to the strong cationic property of the alkali metal, therefore the organic transition metal complex compound may decompose or a side reaction may occur, resulting in a desired organic transition metal complex compound not being obtained in some cases. In addition, since the reactivity of a ligand exchange vary depending on kinds of an alkali metal ion and an atom group having a counter anion, organic transition metal complex compounds which can be produced are restricted. From these reasons, an improved process for producing an organic transition metal complex compound, in which a decomposition reaction or a side reaction never occurs, is needed.
On the other hand, in organic transition metal metallocene complex compounds having a hydrocarbon-based ligand, such as cyclopentadienyl, Jordan et al. have reported a process for synthesizing an organic transition metal metallocene complex compound synthesized by contacting a certain cyclopentadiene having a proton-donor ability with a transition metal dimethylamide compound without the use of alkali metal salt, without a synthetic reaction between a cyclopentadienyl metal salt and a transition metal chloride being carried out in which the cyclopentadienyl metal salt is obtained by a reaction between cyclopentadiene and an organic metal compound, such as butyllithium, or an hydrogenated alkali metal compound, the process being used in a conventional method. In the synthesis method, a side reaction which may occur in the process where an organic transition metal metallocene complex compound is synthesized by using an alkali metal salt, can be prevented; however, the synthesis reaction needs reaction-conditions of high-temperature and long-period, resulting in an increased production cost (see Patent Documents 1 and 2, and Nonpatent Document 1).
Schrock et al. have recently reported that various metathesis reactions including a ring-opening metathesis polymerization can be driven by using a metathesis catalyst of which central metal is tungsten or molybdenum (see Nonpatent Documents 2, 3 and 4). These metathesis catalysts are organic transition metal alkylidene complex compounds with an atom group having a stronger electron-donor ability, such as alkoxy. The metathesis catalyst is synthesized by contacting an alkyl alkali metal salt obtained by contacting a compound having a proton-donor ability, such as alcohol, with sodium, lithium, potassium, or a metal hydride compound thereof, further with an organic metal compound, such as butyllithium, with an organic transition metal complex compound with a halogen or a triflate, which is an atom group having an electron-withdrawing ability, as a ligand, thereby converting it into an alkoxy or the like having a stronger electron-donor ability. In the process, a halogenated alkali metal or a triflate alkali metal salt is produced as a side product.
Therefore, an excessive alkyl alkali metal salt, which is a reactant, remains in the metathesis catalyst thus-produced. When a metathesis reaction is carried out by using such a metathesis catalyst in which these side products and a reactant remain, a reactive substance may be polymerized with the side products or the reactant being polymerization initiators for an anion polymerization, or the metathesis catalyst may be deteriorated or decomposed with a ligand exchange reaction between the side products or the reactant, and active species in the metathesis reaction occurring, due to the strong ionic property of the side products or the reactant. If metal remains in a product prepared with the use of the metathesis reaction, it may affect the physical properties or the color tone of the product adversely.
In the metathesis polymerization reaction, an unsaturated bond in the main chain is generally converted into a saturated bond by the hydrogenation reaction after polymerization. In the process, when an alkali metal salt derived from the synthesis reaction of a metathesis catalyst, that is, a side product or a reactant, is included in the product, a normal hydrogenation reaction may be impaired by deterioration or decomposition of the side product or the reactant, which is caused by a reaction between the side product or the reactant, and a catalyst for the hydrogenation reaction.
Since an alkali metal having a high ionic property is used in the conventional processes for synthesizing a metathesis catalyst, there are various problems, therefore a process for producing a metathesis catalyst without the use of an alkali metal, is needed.
[Patent Document 1] WO 95/32979 pamphlet
[Patent Document 2] U.S. Pat. No. 5,597,935